Diaphragm delivery pump and pumping diaphragm for a diaphragm delivery pump

ABSTRACT

A delivery pump for a delivery fluid comprises at least one valve plate ( 4 ), at least one actuatable pumping diaphragm ( 3 ) attached to the at least one valve plate ( 4 ) in a fluid-tight manner for delivering the delivery fluid, said pumping diaphragm ( 3 ) defining at least one pumping chamber ( 2 ) together with the at least one valve plate ( 4 ) and having at least one free fold ( 16 ), extending over at least one circumferential area of the at least one pumping diaphragm ( 3 ), for changing the volume of the at least one pumping chamber ( 2 ), at least one inlet opening ( 7 ) disposed in the at least one valve plate ( 4 ) for guiding the delivery fluid into the at least one pumping chamber ( 2 ), and at least one outlet opening ( 8 ) disposed in the at least one valve plate ( 4 ) for guiding the delivery fluid out of the at least one pumping chamber ( 2 ).

The invention relates to a diaphragm delivery pump for a delivery fluidand a pumping diaphragm for a diaphragm delivery pump. The inventionrelates in particular to a diaphragm delivery pump to be used inportable fuel cells, electronics cooling devices, gas detecting devices,anesthesia control devices and the like as well as a correspondingpumping diaphragm for such a diaphragm delivery pump. The delivery fluidis to be understood as a medium to be delivered, such as a liquid, a gasor a liquid-gas mixture.

A multitude of diaphragm delivery pumps comprising pumping diaphragmsare known from the prior art. If these diaphragm delivery pumps are madeto have a small size, the delivery rate thereof is generallyunsatisfactory.

Thus it is the object of the invention to provide a diaphragm deliverypump having a high delivery rate and at the same time a small size.Moreover, a pumping diaphragm is to be created that allows for theprovision of such a diaphragm delivery pump having a high delivery rateand at the same time a small size.

This object is attained according to the invention by the features ofclaim 1 and 20. The crux of the invention is that the pumping diaphragmhas at least one free fold extending over at least one circumferentialarea. The circumferential area may be an internal or externalcircumferential area of the pumping diaphragm. The at least one freefold serves to change the volume of the at least one pumping chamberduring the operation. A fold is substantially to be understood as acrease which may also be a rolling crease, for example. The valve platemay be moved with respect to the pumping diaphragm. Conversely, it isalso possible to move the pumping diaphragm with respect to the valveplate.

Further advantageous embodiments of the invention are stated in thesub-claims.

The following is a description of several preferred embodiments of theinvention, taken in conjunction with the enclosed drawings, in which

FIG. 1 shows an exploded view of a diaphragm delivery pump according toa first embodiment;

FIG. 2 shows a longitudinal section through an assembled diaphragmdelivery pump according to the first embodiment, with the pumpingdiaphragm being situated in its lower extreme position;

FIG. 3 shows another longitudinal section through the diaphragm deliverypump according to the first embodiment corresponding to FIG. 2, with thepumping diaphragm being situated in its central position;

FIG. 4 shows another longitudinal section through the diaphragm deliverypump according to the first embodiment corresponding to FIG. 2, with thepumping diaphragm being situated in its upper extreme position;

FIG. 5 shows another longitudinal section through the diaphragm deliverypump according to the first embodiment corresponding to FIG. 2, with thepumping diaphragm being situated in its central position;

FIG. 6 shows a longitudinal section through the separately shown pumpingdiaphragm according to the invention of the diaphragm delivery pumpaccording to the first embodiment, with the shape of said pumpingdiaphragm illustrated thereby corresponding to the shape of the pumpingdiaphragm shown in FIG. 2;

FIG. 7 shows a longitudinal section through the separately shown pumpingdiaphragm of the diaphragm delivery pump according to the firstembodiment, with the shape of said pumping diaphragm illustrated therebycorresponding to the shape of the pumping diaphragm shown in FIGS. 3 and5;

FIG. 8 shows a longitudinal section through the separately shown pumpingdiaphragm of the diaphragm delivery pump according to the firstembodiment, with the shape of said pumping diaphragm illustrated therebycorresponding to the shape of the pumping diaphragm shown in FIG. 4;

FIG. 9 shows an exploded view of a diaphragm delivery pump according toa second embodiment;

FIG. 10 shows a longitudinal section through an assembled diaphragmdelivery pump according to the second embodiment, with the pumpingdiaphragms being situated in an upper extreme position;

FIG. 11 shows a longitudinal section through a diaphragm delivery pumpaccording to the second embodiment corresponding to FIG. 10, with thepumping diaphragms being situated in a transition position between theupper and lower extreme positions;

FIG. 12 shows a perspective assembled view of the diaphragm deliverypump according to the second embodiment;

FIG. 13 shows a longitudinal section through a diaphragm delivery pumpaccording to a third embodiment;

FIG. 14 shows a perspective view of a separately shown pumping diaphragmaccording to the second and third embodiments;

FIG. 15 shows a longitudinal section through the pumping diaphragm shownin FIG. 14 the shape of which illustrated thereby substantiallycorresponds to the shape of the pumping diaphragms shown in FIG. 10;

FIG. 16 shows a longitudinal section through the pumping diaphragm shownin FIG. 14 the shape of which illustrated thereby substantiallycorresponds to the shape of the pumping diaphragms shown in FIG. 13;

FIG. 17 shows a longitudinal section through the pumping diaphragm shownin FIG. 14 the shape of which illustrated thereby is situated in a lowerextreme position of operation;

FIG. 18 shows a longitudinal section through a diaphragm delivery pumpaccording to a fourth embodiment; and

FIG. 19 shows a longitudinal section through a separately shown pumpingdiaphragm according to the fourth embodiment.

The following is a description, taken in conjunction with FIGS. 1 to 5,of a first embodiment of a diaphragm delivery pump 1 according to theinvention. The description initially focuses on the position of apumping diaphragm 3 shown in FIG. 2. The diaphragm delivery pump 1 has apumping chamber 2 with a variable volume, said pumping chamber 2 beingdefined, or delimited, by the flexible, actuatable, thin-walled pumpingdiaphragm 3 and a rigid valve plate 4. When the pumping diaphragm 3,which is made of a fluid-tight elastomer material in this example, isexternally actuated, this causes a delivery fluid to be delivered due tochanging the volume of the pumping chamber 2. The diaphragm deliverypump 1 has a central longitudinal axis 5 and is substantially designedas a solid of revolution.

The valve plate 4 is circular in shape, with a round, central, axialfixing hole passing through said valve plate 4. Moreover, an inletopening 7 and an outlet opening 8 pass through the valve plate 4 in anaxial direction, with the two latter openings 7, 8 being disposed in thevalve plate 4 at an off-center position. The valve plate 4 has a lower,plane contact surface 9. An inclined surface 10 is situated opposite thecontact surface 9. The thickness of the valve plate 4 steadily increasessubstantially from its circumferential outer edge area 11 towards thecentral fixing hole 6; due to the inclined surface 10, the thickness ofthe valve plate 4 is smaller at the edges than at the center thereof.The contact surface 9 is shorter with respect to the inclined surface10, thus forming an annular mount 12 in the outer edge area 11 having acircumferential contact surface facing outward.

The expression “lower”, which is used in this disclosure, refers to theorientation of the diaphragm delivery pump 1 shown in the respectivefigure. The same applies to corresponding expressions used below forother embodiments.

The pumping diaphragm 3 is formed in one-piece, has a circular outershape and is attached to the edge area of the valve plate 4 in afluid-tight manner. The pumping diaphragm 3 may also have a non-circularshape. The pumping diaphragm 3 has a boundary wall 13 situated above theinclined surface 10, with a pivotable outer side wall 14 adjoining saidboundary wall 13. A sealing bead 15 having a circular cross-section isformed at the free end of the side wall 14. The sealing bead 15 bearsagainst the contact surface inside the mount 12 and against an annularprotrusion formed by the inclined surface 10.

The height of the side wall 14 is substantially reduced by half by acircumferential, freely movable fold 16 which permits folding orunfolding, respectively, thereby obtaining a lower side wall portion 17and an upper side wall portion 18. The lower side wall portion 17extends from the sealing bead 15 to the fold 16 while the upper sidewall portion 18 extends from the fold 16 to the boundary wall 13. Theprojected height of the lower side wall portion 17 substantiallycorresponds to the projected height of the upper side wall portion 18.The area of the boundary wall 13 approximately corresponds to theprojected area of the inclined surface 10.

In the position of the pumping diaphragm 3 shown in FIG. 2, at leastpart of the surface of the boundary wall 13 bears against the inclinedsurface 10 in a way that the volume of the pumping chamber 2 isvirtually zero. The upper side wall portion 18 thereby forms anelongation of the boundary wall 13. From the mount 12, the lower sidewall portion 17 extends radially outward towards the top, therebyforming an acute angle α between the lower side wall portion 17 and theupper side wall portion 18. The fold 16, which defines an exact creaseline for the side wall 14, radially protrudes beyond the outer edge area11 of the valve plate 4.

At least part of the surface of a circular, one-piece connection plate19 bears against the contact surface 9 of the valve plate 4, with anaxially protruding, hollow inlet connection 20, which extends along aninlet direction I, and an axially protruding, hollow outlet connection21, which extends along an outlet direction O, being formed thereon. Theinlet connection 20, which is to be connected to a delivery line feedingin the delivery fluid, and the outlet connection 21, which is to beconnected to a delivery line for discharging the delivery fluid, extendaway from the valve plate 4 and are situated in the area of the inletopening 7 or the outlet opening 8, respectively. An axial pair of fixingplates 22 and an axial fixing protrusion 23 are provided on the side ofthe connection plate 19 facing towards the valve plate 4. The pair offixing plates 22 is formed by two spaced-apart, parallel fixing platesand projects into the inlet opening 7. The fixing plates are situatedopposite the inlet connection 20, with their outer surfaces, facing awayfrom one other, bearing against the valve plate 4. One side of aflexible valve reed 24 is fixed between the valve plate 4 and theradially outer fixing plate, i.e. the left-hand fixing plate in FIGS. 2to 5. The free, i.e. non-fixed end of the valve reed 24 is pivotablebetween two extreme positions. When in a shut-off position, theunderside of the horizontal valve reed 24 bears against the free end ofthe fixing plates, thus closing the inlet opening 7 in a fluid-tightmanner in a direction opposite to an inlet direction. When in an openposition, the free end of the valve reed 24 is lifted off the respectivefixing plate, thus enabling the delivery fluid to pass through the inletopening 7. The open position is shown in FIG. 3, while the shut-offposition is shown in FIGS. 2, 4 and 5.

The fixing protrusion 23, on the other hand, engages with the outletopening 8 and is situated opposite the outlet connection 21. One side ofa flexible valve reed 25, whose free end is pivotable between twoextreme positions as well, is clamped between the fixing protrusion 23and the valve plate 4. When in the horizontal shut-off position, thevalve reed 25 shuts off, or closes, the outlet opening 8 in afluid-tight manner in the direction opposite to the outlet directionwhilst enabling the delivery fluid to pass through said outlet opening 8when in the open position. The shut-off position is shown in FIGS. 2 to4, while the open position is shown in FIG. 5.

The valve reed 25 is pivotable downward from its shut-off position, i.e.in the direction of the contact surface 9, whereas the valve reed 24 ispivotable upward from its shut-off position, i.e. away from the contactsurface 9. Pivoting of the valve reeds 24, 25 is limited bycorresponding, inclined surfaces of the valve plate 4. The valve-reeds24, 25 are pressure-controlled.

The valve plate 4 is provided with an angular groove 26 and an angulargroove 27, each of which receiving a sealing ring 28 or 29,respectively. The annular groove 26 surrounds the inlet opening 7, withthe sealing ring 28 placed therein bearing against the inside of theconnection plate 19 in a sealing manner. The annular groove 27, on theother hand, surrounds the outlet opening 8, with the sealing ring 29placed therein bearing against the inside of the connection plate 19 ina sealing manner as well. The sealing rings 28, 29 ensure a fluid-tightconnection between the valve plate 4 and the connection plate 19.

The circular connection plate 19 protrudes beyond the valve plate 4 inthe radial direction. In its outer edge area 30, the connection plate 19has an annular web 31 protruding towards the inclined surface 10 in theaxial direction. The sealing bead 15 of the pumping diaphragm 3 is heldin place by means of the edge area 30, the annular web 31, the contactsurface of the valve plate 4 and the annular protrusion formed by theinclined surface 10. Together, the latter elements form the mount 12 thesealing bead 15 is squeeze-fixed in. with the lower side wall portion 17extending outward from the mount 12 and towards the top.

The connection plate 19 and the valve plate 4 are securelyinterconnected by means of a central, axially oriented connecting screw32 which is further described below. The connection plate 19 bearsagainst the head of the connecting screw 32.

A separate, circular layer of fabric 33 is attached to the surface ofthe side of the boundary wall 13 of the pumping diaphragm 3 facing awayfrom the valve plate 4, said layer of fabric 33 protruding beyond theboundary wall 13 in the radial direction. According to anotherembodiment, the pumping diaphragm 3 is integral with the layer of fabric33.

The free outer edge area of the flexible layer of fabric 33 is clampedbetween a rigid diaphragm ring 34 and a circular, rigid anchor plate 35,with the diaphragm ring 34, which is situated below the anchor plate 35according to the drawings, being screwed to the anchor plate 35 by meansof four fixing screws 36. By means of a central, circular hole, theanchor plate 35 is mounted for axial movement on a plain bearing bush 37surrounding the connecting screw 32.

The anchor plate 35 has a central, circular recess 38 which is opentowards the bottom and is delimited on one side by an annular web 39receiving the fixing screws 36. Moreover, it has an annular recess 40into which an anchor insert 41 of a magnetizable material, such as softiron, is securely inserted. The annular recess 40 is situated on theside of the anchor plate 35 facing away from the recess 38 and is opentowards the top.

Both the pumping diaphragm 3 and the layer of fabric 33 are clamped onthe inside between an inner edge area of the inclined surface 10 of thevalve plate 4 and the lower free end of the bearing bush 37.

A helical compression spring 42 engages with the side of the anchorplate 35 in which the annular recess 40 is situated as well, saidhelical compression spring 42 being slid over the axial bearing bush 37in a way as to rest against a circular, immovable stator plate 43. Thestator plate 43 is provided with an annular recess 44 which is opentowards the bottom and carries a fixed electric annular coil 45. Theannular coil 45, which is conductively connected to a controllablecurrent source (not shown), is disposed opposite the anchor insert 41and cooperates therewith during the operation of the diaphragm deliverypump 1.

The end area of the connecting screw 32 is screwed into a thread of anaxial, central bore 46 formed in the stator plate 43 in a way that thestator plate 35 is immovably fixed with respect to the valve plate 4.The connecting screw 32 passes centrally through the connection plate19, the valve plate 4 adjacent thereto, the pumping diaphragm 3, thelayer of fabric 33, the bearing bush 37 and the anchor plate 35,including the diaphragm ring 34, surrounding the latter. The connectingscrew 32 finally ends in the stator plate 43. The connecting screw 32ensures that the connection plate 19, the valve plate 4, the bearingbush 37 and the stator plate 43 are immovably fixed with respect to eachother.

The following is a description of the function of the describeddiaphragm delivery pump 1 based on FIG. 2. According to FIG. 2, both theinlet opening 7 and the outlet opening 8 are shut-off in a fluid-tightmanner by means of the corresponding valve reed 24 or 25, respectively.The valve reeds 24, 25 are in their rest position. At least part of thesurface of the boundary wall 13 bears against the inclined surface 10 ofthe valve plate 4, with the pumping chamber 2 thus having a minimumvolume approaching zero. The side wall 14 is folded up. An angle α isformed between the lower side wall portion 17 and the upper side wallportion 18 in the area of the fold 16, said angle α being acute. Thefold 16 protrudes beyond the valve plate 4 in the radial direction. Inthis example, the annular coil 45 is current-less. The helicalcompression spring 42 has moved the anchor plate 35 to a position thatcorresponds to the maximum possible distance between the stator plate 43and the anchor plate 35. The valve plate 4 is substantially situated inthe recess 38 of the anchor plate 35. In this position, the clampedlayer of fabric 33 presses the boundary wall 13 against the inclinedsurface 10 of the valve plate 4.

The annular coil 45 is now supplied with an electrical current. Themagnetic field of the annular coil 45 thus generated causes the anchorplate 35, which is mounted for axial movement, to be attracted towardsthe stator plate 43 against the force of the helical compression spring42 by means of the magnetized anchor insert 41. When this happens, theboundary wall 13 is lifted off the valve plate 4 by means of the layerof fabric 33, which is clamped between the diaphragm ring 34 and theanchor plate 35, thereby causing the volume of the pumping chamber 2 toincrease. In a central position, the entire boundary wall 13 now lies ina plane, as can be seen from FIG. 3. The lifting of the boundary wall 13causes the side wall 14 to unfold in the area of the fold 16.Consequently, the angle α becomes more obtuse, with the fold 16 movingin the direction towards the central longitudinal axis 5. The lifting ofthe boundary wall 13 causes a delivery fluid to be drawn into thepumping chamber 2 in an inlet direction I through the inlet connection20 and the inlet opening 7. The influent delivery fluid has pivoted theself-acting valve reed 24 from its rest position to the open position,as shown on the left-hand side of FIG. 3. In FIG. 3, the outlet opening8 is still closed by the valve reed 25. During the suction process, itis impossible for the valve reed 25 to open the outlet opening 8. Thevalve plate 4 has moved out of the recess 38 of the anchor plate 35.

In FIG. 4, the anchor plate 35 has been entirely attracted towards thestator plate 43 by magnetic force, i.e. against the force of the helicalcompression spring 42, with the boundary wall 13 having been moved outof the plane according to FIG. 3 by the clamped layer of fabric 33.Starting from the central area of the pumping diaphragm 3, the boundarywall 13 now extends outward at an upward angle. In this position, boththe inlet opening 7 and the outlet opening 8 are shut off by thecorresponding valve reed 24 or 25, respectively. The pumping chamber 2has a maximum volume. The bearing bush 37 has a chamfer at its lower endso as not to obstruct the upward movement of the boundary wall 13.

The absolute value of the angle between a horizontal line and theboundary wall 13 approximately equals that of the angle between thehorizontal line and the inclined surface 10. Compared to FIG. 3, theangle α between the lower side wall portion 17 and the upper side wallportion 18 has become even more obtuse. Compared to FIG. 3, the fold 16has moved further in the direction of the central longitudinal axis 5.The volume of the pumping chamber 2 is related to the size of the angleα in the area of the fold 16.

In FIG. 5, the annular coil 45 is now current-less again. The helicalcompression spring 42 has pushed the anchor plate 35 away again from thestator plate 35, thereby reducing the volume of the pumping chamber 2 ina way that the delivery fluid has been discharged from the pumpingchamber 2 in the outlet direction O, i.e. through the outlet opening 8and the outlet connection 21. During this process, the valve reed 25 waspivoted from its rest position to the open position in a self-actingmanner while the inlet opening 7 is shut off by the valve reed 24 toavoid an unwanted backflow of delivery fluid.

The helical compression spring 42 subsequently pushes the anchor plate35 in the position shown in FIG. 2, thus reverting back to the positionshown in FIG. 2.

The diaphragm delivery pump 1 virtually comprises an electric lineardrive which performs the described axial up-and-down movement of theunit consisting of the anchor plate 35 and the diaphragm ring 34, andtherefore that of the boundary wall 13 as well, by means of magneticforces. In an initial extreme position, the boundary wall 13 extendsoutward from its central area towards the bottom and, in a subsequentextreme position, from its central area towards the top. During thisprocess, the side wall 14 delimiting the side of the pumping chamber 2is unfolded and folded, thus pivoting outwards and inwards, with thefold 16 being displaced. The position of the fold 16 is related to thecurrent volume of the pumping chamber 2 during the operation. Thepumping diaphragm 3 is single-acting, i.e. the delivery fluid comes incontact with only one side of the boundary wall 13 delimiting thepumping chamber 2 towards the top. A movement of the pumping diaphragm 3causes bending of the portion of the side wall 14 adjoining the sealingbead 15.

FIGS. 6 to 8 once again show separate views of various positions of theused pumping diaphragm 3. Reference is made to the correspondingprevious description of the pumping diaphragm 3. When the pumpingdiaphragm 3 is actuated, the side wall 14 thereof is folded inwards andoutwards again, with the fold 16 being displaced in the radialdirection.

The following is a description, taken in conjunction with FIGS. 9 to 12,of a second embodiment of the diaphragm delivery pump 1′ according tothe invention. Identical parts are referred to with the same referencenumerals as used for the previous embodiment to the description of whichreference is made.

In contrast to the already described diaphragm delivery pump 1 accordingto the first embodiment, the diaphragm delivery pump 1′, which is shownin FIGS. 9 to 12, comprises two separate pumping diaphragms 3 and arotary drive. Compared to the previous diaphragm delivery pump 1, thediaphragm delivery pump 1′ also has two separate pumping chambers 2which are defined by the two pumping diaphragms 3 and the two valveplates 4. According to another embodiment, the two pumping diaphragms 3are integral with one another. In this case, the pumping diaphragm 3 isdouble-acting, having one pumping chamber 2 each on either side.

In this embodiment, an external, conventional electric rotary motor 47is assigned to the diaphragm delivery pump 1′. The electric rotary motor47 has a drive shaft 48, which may be driven by rotation and extendshorizontally according to the figures, and is attached to a fixingbracket 49 substantially having the shape of an L, with the electricrotary motor 47 being screwed to a vertical arm 50 of the fixing bracket49 by means of two fixing screws 51. The drive shaft 48 is guidedthrough a bore 52 formed in the arm 50. Moreover, the fixing bracket 49has a horizontal arm 53 adjoining the vertical arm 50, thus serving as abase plate. A horizontally angled support plate 54 adjoins the upper endof the vertical arm 50, with a mounting protrusion 55 having a circularcross-section vertically protruding from the center of said supportplate 54.

At least part of the surface of the connection plate 19 bears againstthe support plate 54, with the inlet connection 20 and the outletconnection 21 of said connection plate 19 being oriented downwards, asin the previous embodiment shown in FIGS. 1 to 5. The valve plate 4adjoins said connection plate 19. The inclined surface 10 of the valveplate 4 again faces away from the connection plate 19. An upper valveplate 4 is provided opposite the lower valve plate 4, the inclinedsurface 10 thereof facing towards the inclined surface 10 of the lowervalve plate 4. Thus, there is a free space between the two valve plates4 the height of which increases gradually from the inside to the outsidedue to the inclined surfaces 10. Another connection plate 19 bearsagainst the contact surface 9 of the upper valve plate 4, the inletconnection 20 and outlet connection 21 of said connection plate 19extending upward in the opposite direction of the inlet connection 20and outlet connection 21 of the lower valve plate 4. The two inletconnections 20 of the two connection plates 19 are flush with eachother, with the two outlet connections 21 of the two connection plates19 also being aligned with one another. The valve plates 4 areidentical. The connection plates 19 also correspond to one another. Theconnecting screw 32 is replaced by the mounting protrusion 55 whichpasses centrally through the connection plate 19 and the valve plate 4.

A fixing nut 56 bearing against the upper connection plate 19 is screwedon the end of the mounting protrusion 55, thus ensuring that theconnection plates 19 and the valve plates 4 are securely fixed on themounting protrusion 55.

Two identical pumping diaphragms 3, with a layer of fabric 33 disposedtherebetween, are disposed between the two valve plates 4, with themounting protrusion 55 passing centrally through both pumping diaphragms3 an inner area of which is pressed together by the valve plates 4. Atleast part of the surface of the boundary walls 13, which are disposedopposite one another, bears against the layer of fabric 33. The sidewall 14 again starts at the point where the boundary wall 13 is nolonger securely attached to the layer of fabric 33. Thus, a pumpingdiaphragm 3 is disposed on either side of the layer of fabric 33, withthe side walls 14 extending away from the layer of fabric 33. As alreadymentioned, an integral design comprising the two pumping diaphragms 3and the layer of fabric 33 disposed therebetween is also conceivable.

In this embodiment, the layer of fabric 33 is clamped between thediaphragm ring 34 and a connecting rod 57. The connecting rod 57comprises a clamping ring 58 which has a central vertical axis and isscrewed to the diaphragm ring 34 in a way as to clamp the layer offabric 33. Moreover, the connecting rod 57 has a beam 66 with ahorizontal bore 59 having an eccentric 61 being mounted therein which isconnected to the drive shaft 48 in a non-rotational manner by means of arolling-element bearing 60 disposed therebetween.

The following is a short description of the function of this secondembodiment. The function roughly corresponds to the function of theembodiment described before in great detail. During the operation of theelectric rotary motor 47, the drive shaft 48 thereof is set in rotation,thus resulting in a rotation of the eccentric 61. Due to the connectingrod 57, the rotation of the eccentric 61 in turn translates into anapproximately linear vertical axial movement of the clamped layer offabric 33.

FIG. 10 shows an extreme position of the pumping diaphragms 3. In thisposition, the boundary wall 13 of the upper pumping diaphragm 3virtually bears against the inclined surface 10 of the upper valve plate4. Thus, the upper pumping chamber 2 has a minimum volume while thelower pumping chamber, on the other hand, has a maximum volume. As canbe seen in FIG. 10, the side wall 14 of the upper pumping diaphragm 3 isagain folded outwards, thus forming an acute angle α, while the sidewall 14 of the lower pumping diaphragm 3 is pulled apart, thus forming amore obtuse angle α. The fold 16 of the upper pumping diaphragm 3protrudes beyond the fold 16 of the lower pumping diaphragm 3 in theradial direction. The inlet openings 7 and the outlet openings 8 areclosed by the valve reeds 24 or 25, respectively.

During a further rotation of the eccentric 61, the connecting rod 57moves the layer of fabric 33 downwards in the direction of the inclinedsurface 10 of the lower valve plate 4. Thus, the volume of the upperpumping chamber 2 increases while the volume of the lower pumpingchamber 2 is simultaneously reduced. When the size of the upper pumpingchamber 2 increases, delivery fluid is drawn into the upper pumpingchamber 2, thus causing the valve reed 24 to open the inlet opening 7 ofthe upper valve plate 4. The outlet opening 8 of the upper valve plate 4is closed. When the size of the lower pumping chamber 2 is reduced,delivery fluid is forced, or pressed, out of the lower pumping chamber2, thus causing the valve reed 25 to open the outlet opening 8 of thelower valve plate 4. As can be seen from FIG. 11, the inlet opening 7 ofthe lower valve plate 4 is closed during this process. The shape of thelower and upper pumping diaphragms 3 corresponds to the firstembodiment. As far as the further stages are concerned, reference ismade to the previous description.

A connecting hose 62 is provided in FIG. 12 which establishes a flowconnection between the outlet connection 21 of the upper connectionplate 19 and the inlet connection 20 of the lower connection plate 19.The two pumping chambers 2 are thus connected in series so as to obtaina higher compression as compared to the first embodiment. A serialconnection is also obtained by connecting the outlet connection 21 ofthe lower connection plate 19 to the inlet connection 20 of the upperconnection plate 19. The diaphragm delivery pump 1′ may of course alsobe operated with the pumping chambers 2 being connected in parallel,thus enabling a higher flow rate to be obtained as compared to the firstembodiment.

The following is a description, taken in conjunction with FIG. 13, of athird embodiment of the invention. Identical parts are referred to withthe same reference numerals as used for the previous embodiment to thedescription of which reference is made. In contrast to the secondembodiment, the connection plates 19 and the valve plates 4 are rigidlyinterconnected by means of a central, axial hollow pipe 63 whichreplaces the mounting protrusion 55 according to the previousembodiment. The hollow pipe 63 has a radially protruding contact web 64bearing against the outside of the upper connection plate 19. A fixingnut 65 is screwed on the hollow pipe 63, thus fixing the connectionplates 19 and the valve plates 4 with respect to each other. The hollowpipe 63 provides for connecting connection pipes on both sides of thediaphragm delivery pump 1″. As can be seen from FIG. 13, a curved pipeportion 67 is connected to the lower end of the hollow pipe 63 andadditionally, to the outlet connection 21 of the lower connection plate19. This design allows to interconnect the individual connections 20, 21without requiring longer, obstructive pipes. In particular, the twooutlet connections 21 may also be interconnected within the valve plates4. This allows for the construction of a very compact diaphragm deliverypump 1″.

The following is a description, taken in conjunction with FIGS. 14 to17, of an integral unit comprising two pumping diaphragms 3 according tothe second and third embodiments. A separate layer of fabric 33 is notprovided. This unit is double-acting, with both sides of the boundarywall 13 coming in contact with delivery fluid during the delivery of adelivery fluid.

The diaphragms 3 of the embodiments disclosed herein have a sealing bead15 for sealing against the corresponding valve plate 4. Other designsproviding a sealed attachment are of course also conceivable. What isessential is to obtain a secure attachment and, simultaneously, ahermetically sealed connection.

The diaphragm delivery pumps 1, 1′, 1″ according to the invention have amuch higher throughput as compared to similar diaphragm pumps of anidentical size. They may be produced in a simple and cost-effectivemanner. What is essential is that the side wall 14 folds when the volumeof the pumping chamber 2 changes. This is what the fold 16 is providedfor. The side wall 14 may also be provided with several folds 16disposed one above the other. Moreover, the fold 16 may also extend overa partial area of the side wall 14 only, thus allowing an outwardmovement of this partial area of the side wall 14 only. Only the centralpart and the edges of the pumping diaphragm 3 are attached to thecorresponding valve body 4. The fold 16 is freely movable, with neitherits inward nor outward movement being determined by external means. Amultitude of other options are suitable for driving. In this respect, itis not important whether the pumping diaphragm 3 is moved with respectto the valve plate 4 or whether the valve plate 4 is moved with respectto the pumping diaphragm 3.

According to an alternative embodiment, a drive is provided comprising adisc made of piezoelectric ceramics. When an electric voltage is appliedin one direction, said disc is deformed, thereby actuating the pumpingdiaphragm 3. This drive is applicable to both the single-acting pumpingdiaphragm 3 and the double-acting pumping diaphragm. Piezoelectricceramics acquires its special properties in a specific productionprocess enabling the material to convert an electric voltage into amechanical movement or oscillation, and is therefore suitable for use asa component for a drive.

The already described embodiments are provided with an outer side wall14 delimiting the pumping chamber 2 towards the outside. According to analternative embodiment, a pumping diaphragm has a side wall comprisingat least one free fold for changing the volume of the at least onepumping chamber, said free fold extending over at least onecircumferential area of the pumping diaphragm and, in contrast to theprevious embodiments, folding inwards when the volume of the pumpingchamber 2 is reduced by actuating the pumping diaphragm 3. Starting fromthe outer edge area of the valve plate 4, the fold 16 thus foldsinwards, i.e. into the pumping chamber 2. When in the outermostposition, said fold 16 is situated above the outer edge area. Thisdesign is in particular intended for vacuum pumps. Otherwise, thisdiaphragm substantially corresponds to the previous diaphragms.

In the first embodiment of the diaphragm delivery pump shown in FIGS. 1to 5, the pumping chamber 2 is—as already described—defined by thepumping diaphragm 3 and the valve plate 4. A closer look reveals thatthe pumping chamber 2 is delimited towards the outside by the side wall14 of the pumping diaphragm 3 in the radial direction, and by theboundary wall 13 of the pumping diaphragm 3 and the valve plate 4 in theaxial direction. Thus, the boundary wall 13 closes the pumping chamber 2towards the top while the valve plate 4 delimits the pumping chamber 2towards the bottom.

As already mentioned, the diaphragm delivery pumps 1′, 1″ are providedwith two separate pumping chambers 2 disposed one above the other. Theupper pumping chamber 2 is defined by the upper valve plate 4 and theupper pumping diaphragm 3 while the lower pumping chamber 2 is definedby the lower valve plate 4 and the lower pumping diaphragm 3. A closerlook reveals that the upper pumping chamber 2 is delimited by the sidewall 14 of the upper pumping diaphragm 3 in the radial direction, by theupper valve plate 4 towards the top, and by boundary wall 13 of theupper pumping diaphragm 3 towards the bottom. Similarly, this alsoapplies to the lower pumping chamber 2. A closer look reveals that saidlower pumping chamber 2 is delimited by the side wall 14 of the lowerpumping diaphragm 3 in the radial direction, by the boundary wall 13 ofthe lower pumping diaphragm 3 towards the top, and by the lower valveplate 4 towards the bottom. A layer of fabric 33 is disposed between thetwo boundary walls 13 which may be actuated externally from the side. Asalready described, a one-piece design comprising the two pumpingdiaphragms 3 and the layer of fabric 33 is also conceivable.

As shown in FIGS. 14 to 17, a one-piece unit comprising in fact twopumping diaphragms 3 is also conceivable, with no layer of fabric 33being provided. Thus, it is virtually obtained a common, single boundarywall 13 which serves to axially delimit the two pumping chambers 2. Thisunit may again be actuated externally from the side. Therefor, anactuating element is advantageously provided for actuation which engageswith the unit of pumping diaphragms 3 externally from the sidesubstantially in the area of the boundary wall 13, thereby enabling theunit to be actuated. This element may for example be an actuating platehaving an opening adapted to the diameter of the boundary wall 13. Thiselement is situated virtually at the height of the boundary corner 13between the side walls 14 and acts upon the unit externally from theside. However, a separate actuating layer which is suitable fortransmitting forces may also be provided therefor. The actuating elementtakes over the function of the layer of fabric 33 which also forms anactuating element.

The lower pumping chamber 2 may be regarded as first pumping chamber 2while the upper pumping chamber 2 may be regarded as second pumpingchamber 2.

In all embodiments, actuation of the pumping diaphragm 3 is performedexternally from the side by means of a moving element substantiallysurrounding the side wall or side walls 14, respectively, via anabove-described actuating element. The moving element thus appliescorresponding forces for axially actuating the pumping diaphragms 3 inthe radial direction via an actuating element. This type of actuationthus fundamentally differs from conventional bellows pumps in whichactuating forces are only applied in the axial direction. According tothe first embodiment of the diaphragm delivery pump 1, thecircumferential moving element is formed by the diaphragm ring 34 andthe anchor plate 35 while in the diaphragm delivery pump 1′, said movingelement is formed by the diaphragm ring 34 and the clamping ring 58. Thepumping diaphragm/s 3 are thus situated virtually inside the movingelement. The moving element acts upon the radially outer edges of thediaphragm actuating element configured as a layer of fabric 33, with atleast part of the surface thereof being attached to the boundary wall 13of the pumping diaphragm 3. Movement of the pumping diaphragm 3 thusoccurs from the radially outer end and not from the central surface, asin other pumps, thus enabling an increased displacement or swept volumeto be obtained. The fold 16 is situated in an external circumferentialarea of the pumping diaphragm 3.

The following is a description, taken in conjunction with FIGS. 18 and19, of a fourth embodiment of the invention. Identical parts arereferred to with the same reference numerals as used for the previousembodiments to the description of which reference is made.

Like the diaphragm delivery pumps 1′ and 1″ according to the second andthird embodiments, the diaphragm delivery pump 1′″ shown in FIG. 18 hastwo separate pumping chambers 2 disposed one above the other. Thediaphragm delivery pump 1′″ is housed in a substantially two-parthousing 68 comprising a lower pot-like housing part 69 and a pot-likecover part 70. The housing part 69 and the cover part 70 may besnap-locked with one another for interconnection, with a sealing ring113 being disposed therebetween so as to obtain a sealed connection.

The one-piece housing part 69 has a plate-shaped bottom element 71having a central recess 72. A central guide opening 73 is formed in therecess 72. The guide opening 73 is surrounded by inlet openings 74 whichare still situated in the recess 72, therefore passing through thebottom element 71. A side wall 75 adjoins the outer edge of the bottomelement 71, said side wall 75 being a component of the housing part 69.An outwardly projecting retaining shoulder 76 is formed in the side wall75 in a way that the side wall 75 expands in a step-like manner withrespect to the bottom element 71 in the area of the retaining shoulder76. An outwardly projecting flange 77 is formed at the end of the sidewall 75 facing away from the bottom element 71, said flange 77 beingprovided with several snap-lock openings 78.

The one-piece cover part 70 has a cover plate 79 which is parallel tothe bottom element 71 and has a central projection 80. The projection 80defines a chamber and projects outward from the cover plate 79. Theprojection 80 and the guide opening 73 are flush with each other. Theprojection 80 is surrounded by inlet openings 81 which are situated inthe cover plate 79, thus passing through the latter. The cover plate 79extends outward from the projection 80, thus forming a retaining step 82projecting towards the bottom element 71. A side wall 83 adjoins theedge of the cover plate 79. A reinforced end piece is situated at thelower end of the side wall 83, with several resilient snap-lock bodies84 projecting downward being attached to said end piece. The snap-lockbodies 84 are dimensioned and disposed in a way as to cooperate with thesnap-lock openings 78 formed in the flange 77 in a snap-locking manner.The snap-lock bodies 84 and the corresponding snap-lock openings 78enable the housing part 69 and the cover part 70 to be detachablyinterconnected, with the cover part 70 defining an upper partial housingspace 85 and the housing part 69 defining a lower partial housing space86. The two partial housing spaces 85, 86 are interconnected in a way asto obtain a common housing space 87 defined by the housing 68.

The actual diaphragm delivery pump 1′″ is housed in the housing space87. The diaphragm delivery pump 1′″ has—as mentioned—two separatepumping chambers 2 and a magnetic drive. The diaphragm delivery pump 1according to the first embodiment is provided with a magnetic drive aswell to which reference is principally made. However, other drives areconceivable for this embodiment as well.

Accordingly, the diaphragm delivery pump 1′″ has a lower and an upper ora first and a second pumping chamber 2, respectively, having a variablevolume, with each of which being defined by a pumping diaphragm 3′ and avalve plate 4′. According to another embodiment, the two pumpingdiaphragms 3′ are integral with one another. The pumping diaphragm 3′according to said integral design is double-acting, having a pumpingchamber 2 on either side.

Each valve plate 4′ has an outer annular base body 88 and an innerannular retaining body 89. The inner retaining bodies 89 oppose oneanother while the base bodies 88 virtually face away from one another.An outer edge area of the upper base body 88 bears against the inside ofthe retaining step 82, thereby fixing the upper base body 88. Eachretaining body 89 has at least one projection 90 engaging with at leastone corresponding recess 91 disposed in the adjacent base body 88 so asobtain a secure connection between said bodies 88, 89. A flexible valveelement 92 is clamped between each base body 88 and the correspondingretaining body 89, said valve element 92 being self-acting orpressure-controlled, respectively.

Several inlet openings 7′ projecting into the corresponding, adjacentpumping chamber 2 are formed in each base body 88. When in theirrespective shut-off position, corresponding areas of the valve elements92 cover the inlet openings 7′, thereby closing the latter in afluid-tight manner. In FIG. 18, all valve elements 92 are situated insaid shut-off position. In an open position, not shown, the respectivearea of the valve element 92 is lifted off the corresponding base body88, thus opening the corresponding inlet opening 7′ for the deliveryfluid to enter the corresponding pumping chamber 2. Each retaining body89 has outlet openings 8′ which are in a flow-connection with therespective pumping chamber 2.

In a shut-off position, the valve elements 92 also close the end sidesof the respective outlet openings 8′ by means of other areas. Thecorresponding areas of the valve elements 92 may be lifted off saidshut-off position in a pressure-controlled manner.

Each pumping diaphragm 3′ forms one piece and has an inner boundary wall13′, with an inner side wall 14′ pivotally disposed adjacent thereto. Asealing bead 15 having a circular cross-section is formed at the freeend of the side wall 14′. The height of each side wall 14′ is reduced byhalf by a circumferential fold 16 which allows for folding in a way thata lower side wall portion 17 and an upper side wall portion 18 areobtained. In the intermediate position of the pumping diaphragms 3′shown in FIG. 18, the folds 16 radially protrude towards the inside withrespect to the base bodies 88, with the side wall portions 17, 18 of thepumping diaphragm 3′ radially converging in the inward direction. Thefold 16 is situated in an internal circumferential area of the pumpingdiaphragm 3′. The bead 15 of the upper pumping diaphragm 3′ is situatedin a mount 12′ between the cover plate 79 and the upper base body 88disposed adjacent thereto.

As can be seen from FIG. 18, the two pumping diaphragms 3′ areinterconnected via the surfaces of their boundary walls 13′, with therespective side walls 14′ extending away from one another, starting fromthe boundary walls 13′. A radially outer edge area 93 of the boundarywalls 13′ of the pumping diaphragms 3′ is fixed between the retainingbodies 89. The edge area 93 is fixed by means of a radially outer edgearea 94 of the retaining bodies 89.

The upper pumping chamber 2 is delimited towards the bottom by theboundary wall 13′ and radially towards the inside by the side wall 14′of the upper pumping diaphragm 3′. The upper pumping chamber 2 isdelimited both radially towards the outside and towards the top by theupper valve plate 4′.

The lower pumping chamber 2 is delimited towards the top by the boundarywall 13′ and radially towards the inside by the side wall 14′ of thelower pumping diaphragm 3′. The lower pumping chamber 2 is delimitedboth radially towards the outside and towards the bottom by the lowervalve plate 4′.

A radially inner edge area 95 of the pumping diaphragms 3′ is fixed toan actuating rod 96. The side walls 14′ extend away from said edge area95 of the boundary walls 13′ thereof. The actuating rod 96 has a fixingportion 97 so as to provide a connection between the pumping diaphragms3′ and the actuating rod 96, said fixing portion 97 being encircled byan upper and a lower fixing ring 98. The edge area 95 is clamped betweenthe two fixing rings 98 for fixing, with the side walls 14′ encirclingthe fixing portion 97 and the fixing rings 98. The fixing portion 97 andthe fixing rings 98 are thus situated in the centre of the pumpingdiaphragms 3′. The central longitudinal axis of the fixing portion 97 isaligned with the central longitudinal axis of the pumping diaphragms 3′.

The actuating rod 96 is mounted for displacement in an upper mountingunit 99 and a lower mounting unit 100, with the upper mounting unit 99being inserted into the cover plate 79 in the area of the projection 80and the mounting unit 100 being inserted into the bottom element 71 inthe area of the recess 72.

The bead 15 of the lower pumping diaphragm 3′ is situated in a mount 12′which is provided between the lower base body 88 and a fixing plate 101disposed adjacent to the latter.

The fixing plate 101 has a mounting opening 102 in its centre into whicha mounting unit 103 is inserted for mounting the actuating rod 96. Adriving portion 104 of the actuating rod 96 passes through the mountingunit 103, said driving portion 104 adjoining the lower end of the fixingportion 97. The fixing plate 101 has an external retaining protrusion105 in the radial direction which rests upon the retaining shoulder 76of the housing part 69 in a way that the fixing plate 101 is supportedby the housing part 69.

Moreover, the fixing plate 101 is provided with inlet openings 106 whichare flush with the inlet openings 7′. The fixing plate 101 supports thevalve plates 4′ and the pumping diaphragms 3′.

The actual drive unit of the diaphragm delivery pump 1′″ is situatedbelow the fixing plate 101. The drive unit comprises an annular coil 45′which is conductively connected to a controllable current source. Theannular coil 45′ encircles an internal space 107 penetrated by thedriving portion 104 of the actuating rod 96. According to FIG. 18, amagnet body 108 comprising two magnets 109, 111 and a piece of iron 110disposed therebetween is situated on the driving portion 104 in theinternal space 107 of the annular coil 45′.

The drive unit is situated in the housing part 69 along with the lowervalve plate 4′ and the lower pumping diaphragm 3′. The upper valve plate4′ and the upper pumping diaphragm 3′, on the other hand, are situatedin the cover part 70.

The following is a description of the function of the diaphragm deliverypump 1′″ based on the intermediate position shown in FIG. 18. When theannular coil 45′ is supplied with an electrical current, an alternatingmagnetic field is generated which acts upon the magnet body 108, therebycausing an upward/downward movement of the actuating rod 96 along itscentral longitudinal axis or the central longitudinal axis 5,respectively. This also causes the two pumping diaphragms 3′ to beactuated radially from the inside, said pumping diaphragms 3′ beingrigidly connected to the actuating rod 96 by means of the fixing rings98. On the outside, however, the pumping diaphragms 3′ are radiallyfixed. When the actuating rod 96 moves upwards in the direction of thecover plate 79, the volume of the lower pumping chamber 2 increaseswhile the volume of the upper pumping chamber 2 is simultaneouslyreduced to a corresponding extent. When the volume of the lower pumpingchamber 2 increases, the fold 16 moves from the inside to the outside inthe radial direction, thus causing the angle α to become more obtuse.The fold 16 thus moves away from the central longitudinal axis 5. Theincreasing volume of the lower pumping chamber 2 causes a delivery fluidto be drawn into the lower pumping chamber 2 through the inlet openings74, 106, 7′, with the valve element 92 being correspondingly lifted offthe inlet opening 7′ due to the influent delivery fluid. During thisprocess, the outlet openings 8′ are closed by the valve element 92. Whenthe lower pumping chamber 2 increases in size, the upper pumping chamber2 is reduced in size. This reduction causes the free fold 16 of theupper pumping diaphragm 3′ to move radially inwards in the direction ofthe central longitudinal axis 5. The delivery fluid in the upper pumpingchamber 2 is discharged from the upper pumping chamber 2 through theoutlet openings 8′, with the valve element 92 being correspondinglylifted off the outlet openings 8′ by the delivery fluid, and thedelivery fluid being discharged from the housing 68 through an outlet112. The outlet 112 in the shape of a connection is a component of thecover part 70. When the upper pumping chamber 2 is reduced in size, theinlet openings 7′ are closed by the valve elements 92. For completedraining, each of the retaining bodies 89 has an inclined surface 10serving as a rest for the boundary wall 13′.

During the described movement, the upper end of the actuating rod 96furthermore penetrates into the chamber defined by the projection 80 ofthe cover plate 79 while the magnet body 108 partially moves out of theinternal space 107 of the annular coil 45′. A corresponding actuation ofthe annular coil 45′ allows the polarity of the generated magnetic fieldto be reversed, thereby causing a downward movement of the actuating rod96 in the direction of the bottom element 71. The upper descriptionapplies correspondingly. The upper pumping chamber 2 is thus increasedin size while that of the lower pumping chamber 2 is reduced. When theupper pumping chamber 2 increases in size, a delivery fluid is drawninto the upper pumping chamber 2 through the openings 81 and 7′, therebyagain actuating the valve element 92. At the same time, the deliveryfluid in the upper pumping chamber 2 is discharged from the housing 68through the outlet opening 8′ and the outlet 112. When the actuating rod96 moves downwards, the magnet body 108 moves into the recess 72.

An oscillating vibration drive is formed by the annular coil 45′ and themagnet body 108, said vibration drive operating the pumping diaphragms3′, thereby effecting the above processes.

In contrast to the previous embodiments, the pumping diaphragms 3′ ofthis embodiment are actuated internally from the side by means of fixingrings 98 which are situated within the side walls 14′ of the pumpingdiaphragms 3′. The boundary wall 13′ applies forces to the boundarywalls 3′ from inside in the radial direction, thereby actuating thepumping diaphragms 3′.

The diaphragm delivery pumps 1, 1′, 1″, 1′″ may be produced in aparticularly cost-effective manner. Moreover, the pumping chambers 2 arehermetically sealed. This is due to the fact that each of the pumpingchambers 2 is only defined by a pumping diaphragm 3, 3′ and a valveplate 4, 4′. Conventional bellows pumps, on the other hand, generallyrequire a valve plate, a cylindrical bellows and a closure elementdisposed opposite the valve plate. The bellows must therefore beattached to both the valve plate and the closure element in afluid-tight manner.

1. Delivery pump for a delivery fluid comprising a) at least one valveplate; b) at least one pumping diaphragm which is displaceable withrespect to the valve plate for delivering the delivery fluid, saiddiaphragm i) being attached to the at least one valve plate in afluid-tight manner whilst defining at least one pumping chamber togetherwith the at least one valve plate, and ii) having at least one free foldfor changing the volume of the at least one pumping chamber, said foldextending over at least one circumferential area of the at least onepumping diaphragm; c) at least one inlet opening disposed in the atleast one valve plate for guiding the delivery fluid into the at leastone pumping chamber, and d) at least one outlet opening disposed in theat least one valve plate for guiding the delivery fluid out of the atleast one pumping chamber.
 2. Delivery pump according to claim 1,wherein the at least one pumping diaphragm has a circular outer shape.3. Delivery pump according to claim 1, wherein the at least one freefold extends over the entire circumference of the at least one pumpingdiaphragm.
 4. Delivery pump according to claim 1, wherein the at leastone free fold is situated in a side wall of the at least one pumpingdiaphragm.
 5. Delivery pump according to claim 1, wherein the at leastone valve plate has an outer edge area, with the at least one pumpingdiaphragm being attached to the outer edge area in a fluid-tight manner.6. Delivery pump according to claim 5, wherein a central longitudinalaxis, with the at least one free fold protruding beyond the outer edgearea in the radial direction.
 7. Delivery pump according to claim 1,wherein the at least one free fold defines at least one crease line forthe at least one pumping diaphragm.
 8. Delivery pump according to claim7, wherein the crease line causes the side wall to fold.
 9. Deliverypump according to claim 1, wherein the at least one pumping diaphragmfurthermore comprises a boundary wall for axially delimiting the atleast one pumping chamber.
 10. Delivery pump according to claim 9,wherein the boundary wall adjoins the side wall.
 11. Delivery pumpaccording to claim 9, wherein the at least one pumping chamber isdefined by a valve plate, a side wall and a boundary wall.
 12. Deliverypump according to claim 1, comprising at least a second valve plate,wherein the two valve plates and the at least one pumping diaphragmdefine two pumping chambers.
 13. Delivery pump according to claim 12,wherein each pumping chamber is defined by a side wall and a boundarywall.
 14. Delivery pump according to claim 1, wherein the boundary wallis actuatable for relative displacement of the at least one pumpingdiaphragm with respect to the at least one valve plate.
 15. Deliverypump according to claim 14, wherein the relative displacement betweenthe at least one pumping diaphragm and the at least one valve plate isforced by lateral external forces.
 16. Delivery pump according to claim1, wherein the relative displacement between the at least one pumpingdiaphragm and the at least one valve plate is forced by lateral internalforces.
 17. Delivery pump according to claim 16, wherein the at leastone free fold radially protrudes beyond an inner edge area of the atleast one valve plate.
 18. Delivery pump according to claim 16, whereinan actuating element passes through the at least one pumping diaphragmfor actuating the same.
 19. Delivery pump according to claim 18, whereinthe side wall extends adjacent to the actuating element and encirclesthe latter.
 20. Pumping diaphragm for a delivery pump having at leastone pumping chamber, comprising at least one free fold for changing thevolume of the at least one pumping chamber, with the at least one freefold extending over at least one circumferential area of the at leastone pumping diaphragm.